Where it is
Inside the vertebral canal from the foramen magnum to about L1–L2 in adults, where it tapers into the conus medullaris; below that, nerve roots continue as the cauda equina.
What it does
Ascending tracts carry sensation up; descending tracts carry motor commands down. Reflex arcs (such as the knee jerk) work at the level of the cord.
Clinical relevance
- C1–C4 injuries can cause loss of breathing; C5–C8 injuries cause tetraplegia; thoracic and lumbar injuries cause paraplegia.
- Spinal shock causes temporary flaccid paralysis and loss of reflexes below the injury.
- Neurogenic shock (injuries above T6) causes hypotension and bradycardia.
Nursing focus
- Maintain spinal alignment and log roll; assess respiratory function closely in cervical injuries.
- Check sensation using dermatome landmarks: T4 at the nipples, T10 at the umbilicus.